There are "favorites", but I never use them. The tivo model is more about season passes and wishlists to gather content rather than manipulating channels in realtime. Takes a bit of transition, but its worth it.

You can tag your favorite channels in the channels list under Settings with a .

Then, under Live TV, press the Guide button, followed by Enter (Not Select), Go up 1 or 2 lines to scroll with left or Right for "All", "Channels I Receive", or "Favorites", go back down to bottom to save and return to Guide.